Isosorbide Dinitrate – A Comprehensive Guide for Medical Use

 

Comprehensive blog on Isosorbide Dinitrate: its uses, mechanism, dosage, side effects, contraindications, and brand names. A must-read for medical professionals and students.

Table of Contents:

1. Introduction  

2. Mechanism of Action  

3. Pharmacokinetics & Pharmacodynamics  

4. Indications  

5. Drug of Choice For  

6. Contraindications  

7. Side Effects  

8. Drug Interactions  

9. Dosage  

10. Brand Names & Price  

11. Conclusion  

1. Introduction:

Isosorbide dinitrate is a nitrate-class vasodilator used primarily in the treatment and prevention of angina pectoris and heart failure. It reduces myocardial oxygen demand by dilating blood vessels, easing the workload on the heart.

2. Mechanism of Action:

It is converted to nitric oxide in vascular smooth muscle, which activates guanylate cyclase, increasing cyclic GMP. This leads to relaxation of vascular smooth muscles, reducing preload and afterload.

3. Pharmacokinetics & Dynamics:

- *Absorption:* Well-absorbed orally  

- *Onset:* 15–30 minutes (oral)  

- *Half-life:* ~1 hour (prodrug, active metabolites prolong effect)  

- *Excretion:* Renal  

- *Bioavailability:* Variable (due to first-pass metabolism)

4. Indications:

- Angina pectoris (prophylaxis)

- Congestive heart failure (adjunct)  

- Esophageal spasms (off-label)  

5. Drug of Choice For:

- Chronic stable angina  

- Acute decompensated heart failure (with hydralazine in African American patients)

6. Contraindications:

- Hypotension  

- Severe anemia  

- Use with PDE5 inhibitors (e.g., sildenafil)  

- Increased intracranial pressure  

- Allergy to nitrates  

7. Side Effects:

- Headache  

- Dizziness  

- Flushing  

- Hypotension  

- Reflex tachycardia  

- Nausea

8. Drug Interactions:

- *PDE5 inhibitors*: Severe hypotension  

- *Antihypertensives*: Additive effect  

- *Alcohol*: Increases risk of side effects

9. Dosage:

- *Angina (Oral):* 5–40 mg 2–3 times daily  

- *Heart failure:* Usually combined with hydralazine, adjusted individually  

- *Note:* A nitrate-free interval (e.g., nighttime) is needed to prevent tolerance

10. Brand Names & Price:

- *Brand Names:* Isordil, Sorbitrate, Dilatrate-SR  

- *Price (varies):* 10–50/month depending on formulation and brand  

11. Conclusion:

Isosorbide dinitrate remains a vital tool in managing angina and heart failure. Its proper use, awareness of interactions, and tolerance management are essential for therapeutic success.